Grunn, the Lonely King is a uncommon Legendary Creature — Ape Warrior card from Dominaria (DOM), collector number 165. Current market price: $0.17 (foil $2.82), TCGplayer market prices via Scryfall.
Kicker {3} (You may pay an additional {3} as you cast this spell.) If Grunn was kicked, it enters with five +1/+1 counters on it. Whenever Grunn attacks alone, double its power and toughness until end of turn.